As 5G goes far beyond mobile and will eventually become the network that bridges all networks together, a new sophisticated service-based architecture (SBA) is being designed by the Third Generation Partnership Project (3GPP). Although many of the network functions featured in the 5G SBA come from existing ones currently active in 2G/3G and 4G networks, novel ones such as the network slice selection function (NSSF) are being introduced. Based on a service provider survey and discussions with many vendors, this report analyzes dozens of functions and then sizes and forecasts the 5G Core SBA market by focusing on the most imminent functions to be implemented by service providers in each region.